Pharmacokinetics, biodistribution, efficacy and safety of N-octyl-O-sulfate chitosan micelles loaded with paclitaxel

Polysorbate 80 coated poly (ɛ-caprolactone)-poly (ethylene glycol)-poly (ɛ-caprolactone) micelles for paclitaxel delivery

In this article, polysorbate 80 coated poly (ɛ-caprolactone)-poly (ethylene glycol)-poly (ɛ-caprolactone) (PCEC) micelles were successfully prepared for paclitaxel (PTX) delivery. The particle size distribution, morphology, drug loading, encapsulation efficiency and sustained release profile of the micelles were studied in detail. The safety of the micelle formulation was evaluated by MTT assay on HEK293 cells. And the encapsulated PTX in the micelles remained potent antitumor effect on C6 glioma cells. The pharmacokinetic study showed that the PCEC micelles coated with polysorbate 80 altered the biodistribution pattern and increased PTX concentration in the brain significantly compared to the uncoated micelles and the free drug after intravenous injection. The results indicated that polysorbate 80 coated PCEC micelles might be a candidate for PTX delivery for brain tumor chemotherapy.

Amphiphilic polymeric micelles as the nanocarrier for peroral delivery of poorly soluble anticancer drugs

INTRODUCTION

Many amphiphilic copolymers have recently been synthesized as novel promising micellar carriers for the delivery of poorly water-soluble anticancer drugs. Studies on the formulation and oral delivery of such micelles have demonstrated their efficacy in enhancing drug uptake and absorption, and exhibit prolonged circulation time in vitro and in vivo.

AREAS COVERED

In this review, literature on hydrophobic modifications of several hydrophilic polymers, including polyethylene glycol, chitosan, hyaluronic acid, pluronic and tocopheryl polyethylene glycol succinate, is summarized. Parameters influencing the properties of polymeric micelles for oral chemotherapy are discussed and strategies to overcome main barriers for polymeric micelles peroral absorption are proposed.

EXPERT OPINION

During the design of polymeric micelles for peroral chemotherapy, selecting or synthesizing copolymers with good compatibility with the drug is an effective strategy to increase drug loading and encapsulation efficiency. Stability of the micelles can be improved in different ways. It is recommended to take permeability, mucoadhesion, sustained release, and P-glycoprotein inhibition into consideration during copolymer preparation or to consider adding some excipients in the formulation. Furthermore, both the copolymer structure and drug loading methods should be controlled in order to get micelles with appropriate particle size for better absorption.

Pharmacokinetics, tissue distribution and anti-tumour efficacy of paclitaxel delivered by polyvinylpyrrolidone solid dispersion

Objectives

Paclitaxel is a potent anti-cancer drug that has exhibited clinical activity against several tumours. Unfortunately, serious side effects are associated with Taxol, the commercial formulation of paclitaxel, which contains Cremophor EL (CrEL). Currently, the main focus of developing paclitaxel formulations is on improving efficacy and reducing toxicity. A novel, Cremophor-free, paclitaxel solid dispersion (PSD) was prepared in our laboratory previously. The primary aim of this study was to evaluate the pharmacokinetics, tissue distribution, acute toxicity and anti-tumour efficacy of the PSD compared with Taxol.

Methods

SD rats were used to examine the pharmacokinetics and tissue distribution of PSD. The acute toxicity of PSD was evaluated in ICR mouse. The anti-tumor activity of PSD was assessed in an in vivo anti-tumor nude mice model inoculated with human SKOV-3 cancer cells.

Key findings

The two formulations presented different pharmacokinetic behaviour. The plasma AUC of paclitaxel in the PSD was 5.84-fold lower than that of Taxol, and the mean residence time, total body clearance and apparent volume of distribution of paclitaxel in the PSD were increased by 1.73, 4.67 and 8.57 fold, respectively. However, the two formulations showed similar tissue distribution properties. CrEL, the vehicle in Taxol, decreased the clearance of paclitaxel from plasma. The LD50 (median lethal dose) was 34.8 mg/kg for Taxol, whereas no death was observed at 160 mg/kg for the PSD. The anti-tumour activity of PSD was similar to that of Taxol at a dose of 15 mg/kg. Most importantly, the improved tolerance of PSD enabled a higher administrable dose of paclitaxel, which resulted in improved efficacy compared with Taxol administered at its maximum tolerated dose.

Conclusions

These results suggest that the PSD, a CrEL-free formulation, is a promising approach to increase the safety and efficacy of paclitaxel.

N-octyl-O-sulfate chitosan-modified liposomes for delivery of docetaxel: preparation, characterization, and pharmacokinetics

A N-octyl-O-sulfate chitosan (NOSC) anchored liposome system was developed as the carrier for antitumor drug, docetaxel (DTX). The physicochemical and pharmacokinetic properties of NOSC-modified DTX liposomes (NDLs) were evaluated compared with the conventional DTX liposomes (DLs) and commercial dosage form of DTX, Taxotere(®). The results showed that NDLs had DTX-loading rate of 3.41%, entrapment efficiency of 61.73%, narrow distributed particle size of 147.6±1.9nm, and high zata potential of -44.2±3.9mV. The decreased permeability of the liposome bilayer was evaluated by release behavior of calcein (CAL) from the internal phase of NOSC-modified CAL liposomes (NCLs) and enhanced stability of NDLs owed to shielding effect of sulfonic shell from adsorption by BSA. After i.v. administration at the dose of 12mg/kg, a significant increase in the AUC, MRT, and T(1/2β) (P<0.05) was observed in NDLs group compared with DLs and Taxotere(®) group. AUC(0-∞) of NDLs was 6.14 and 1.55 times higher than Taxotere(®) and DLs, respectively, and MRT(0-∞) of NDLs was 5.77 and 1.37 times higher than Taxotere(®) and DLs, respectively. All these results suggested that anchored liposomes could increase the stability of DTX in vitro and in vivo, as compared with conventional liposomes and Taxotere(®). Therefore, NOSC as a polymeric shell to liposomes was effective to enhance the stability of liposomes containing DTX.

Supramolecular micellar nanoaggregates based on a novel chitosan/vitamin E succinate copolymer for paclitaxel selective delivery

Background

Nowadays, many cytotoxic anticancer drugs exhibit low solubility and poor tumor selectivity, which means that the drug formulation is very important. For example, in the case of paclitaxel (PTX), Cremophor EL^® (BASF, Ludwigshafen, Germany) needs to be used as a solubilizer in its clinical formulation (Taxol^®, Bristol-Myers Squibb, New York, NY), although it can cause serious side effects. Nanomicellar systems are promising carriers to resolve the above problems, and the polymer chosen is the key element.

Methods

In this study, a novel amphiphilic chitosan/vitamin E succinate (CS-VES) copolymer was successfully synthesized for self-assembling polymeric micelles. Proton nuclear magnetic resonance spectroscopy and infrared were used to characterize the molecular structure of the copolymer. The PTX-loaded CS-VES polymeric micelles (PTX-micelles) were characterized by dynamic light scattering, transmission electron microscopy, X-ray diffraction, and differential scanning calorimetry.

Results

The critical micelle concentration of CS-VES was about 12.6 μg/mL, with the degree of amino group substitution being 20.4%. PTX-micelles were prepared by a nanoprecipitation/dispersion technique without any surfactant being involved. PTX-micelles exhibited a drug loading as high as 21.37% and an encapsulation efficiency of 81.12%, with a particle size ranging from 326.3 to 380.8 nm and a zeta potential of +20 mV. In vitro release study showed a near zero-order sustained release, with 51.06%, 50.88%, and 44.35% of the PTX in the micelles being released up to 168 hours at three drug loadings of 7.52%, 14.09%, and 21.37%, respectively. The cellular uptake experiments, conducted by confocal laser scanning microscopy, showed an enhanced cellular uptake efficiency of the CS-VES micelles in MCF-7 cells compared with Taxol. The PTX-micelles exhibited a comparable but delayed cytotoxic effect compared with Taxol against MCF-7 cells, due to the sustained-release characteristics of the nanomicelles. More interestingly, blank nanomicelles based on CS-VES copolymer demonstrated significant cytotoxicity against MCF-7 cells.

Conclusion

The supramolecular micellar aggregates based on CS-VES copolymer is a promising nanocarrier and efficacy enhancer when used as an anticancer drug-delivery system.

Chitosan-Grafted Copolymers and Chitosan-Ligand Conjugates as Matrices for Pulmonary Drug Delivery

Recently, much attention has been given to pulmonary drug delivery by means of nanosized systems to treat both local and systemic diseases. Among the different materials used for the production of nanocarriers, chitosan enjoys high popularity due to its inherent characteristics such as biocompatibility, biodegradability, and mucoadhesion, among others. Through the modification of chitosan chemical structure, either by the addition of new chemical groups or by the functionalization with ligands, it is possible to obtain derivatives with advantageous and specific characteristics for pulmonary administration. In this paper, we discuss the advantages of using chitosan for nanotechnology-based pulmonary delivery of drugs and summarize the most recent and promising modifications performed to the chitosan molecule in order to improve its characteristics.

Dual targeting folate-conjugated hyaluronic acid polymeric micelles for paclitaxel delivery

A series of novel self-assembled hyaluronic acid derivatives (HA-C(18)) grafted with hydrophobic octadecyl moiety and further dual targeting folic acid-conjugated HA-C(18) (FA-HA-C(18)) were synthesized. With the increase in the degree of substitution of octadecyl group from 12.7% to 19.3%, the critical micellar concentration of HA-C(18) copolymers decreased from 37.3 to 10.0 μg/mL. Paclitaxel (PTX) was successfully encapsulated into the hydrophobic cores of the HA-C(18) and FA-HA-C(18) micelles, with encapsulation efficiency as high as 97.3%. The physicochemical properties of the polymeric micelles were measured by DLS, TEM and DSC. Moreover, in vitro release behavior of PTX was investigated by dialysis bag method and PTX was released from micelles in a near zero-order sustained manner. In vitro antitumor activity tests suggested PTX-loaded HA-C(18) and FA-HA-C(18) micelles exhibited significantly higher cytotoxic activity against MCF-7 and A549 cells compared to Taxol at a lower PTX concentration. The cellular uptake experiments were conducted by quantitative assay of PTX cellular accumulation and confocal laser scanning microscopy imaging of coumarin-6 labeled HA-C(18) and FA-HA-C(18) micelles in folate receptor overexpressing MCF-7 cells. Folate and CD44 receptor competitive inhibition studies performed by fluorescence microscopy imaging suggested intracellular delivery of HA-C(18) and FA-HA-C(18) micelles were efficiently taken up via CD44 receptor-mediated endocytosis. The folate receptor-mediated endocytosis further enhanced internalized amounts of FA-HA-C(18) micelles in MCF-7 cells, as compared with HA-C(18) micelles. The internalization pathways of PTX-loaded HA-C(18) and FA-HA-C(18) micelles might include clathrin-mediated endocytosis, caveolae-mediated endocytosis and macropinocytosis. Therefore, the present study suggested that HA-C(18) and FA-HA-C(18) copolymers as biodegradable, biocompatible and cell-specific targetable nanostructure carriers, are promising nanosystems for cellular and intracellular targeting delivery of hydrophobic anticancer drugs.

Pharmacokinetics, efficacy, and safety evaluation of docetaxel/hydroxypropyl-sulfobutyl-β-cyclodextrin inclusion complex

Hydroxypropyl-sulfobutyl-β-cyclodextrin (HP-SBE-β-CD) inclusion complex was developed and used as a drug delivery system for DTX (DTX/HP-SBE-β-CD). The objective of the present study was to evaluate and compare the biological properties of DTX/HP-SBE-Β-CD with Taxotere®. The pharmacokinetics, biodistribution, antitumor efficacy in vivo and in vitro, and safety evaluation of DTX/HP-SBE-β-CD were studied. The most significant finding was that it was possible to prepare a Polysorbate-80-free inclusion complex for DTX. Studies based on pharmacokinetics, biodistribution, and antitumor efficacy indicated that DTX/HP-SBE-β-CD had similar pharmacokinetic properties and antitumor efficacy both in vitro and in vivo as Taxotere®. Fortunately, this new drug delivery system attenuated the side effects when used in vivo. As a consequence, DTX/HP-SBE-β-CD may be a promising alternative to Taxotere® for cancer chemotherapy treatment with reduced side effects. The therapeutic potential against a variety of human tumors and low toxicity demonstrated in a stringent study clearly warrant clinical investigation of DTX/HP-SBE-β-CD for possible use against human tumors.

Paclitaxel loaded PEG(5000)-DSPE micelles as pulmonary delivery platform: formulation characterization, tissue distribution, plasma pharmacokinetics, and toxicological evaluation

The objective of the present study was to evaluate the potential of paclitaxel loaded micelles fabricated from PEG(5000)-DSPE as a sustained release system following pulmonary delivery. PEG(5000)-DSPE micelles containing paclitaxel were prepared by solvent evaporation technique followed by investigation of in vitro release of paclitaxel in lung simulated fluid. Tissue distribution and plasma pharmacokinetics of the PEG-lipid micelles after intratracheal and intravenous administrations were investigated in addition to intratracheally administered taxol. Finally, toxicological profile of PEG(5000)-DSPE was investigated. Paclitaxel was successfully formulated in PEG-lipid micelles with encapsulation efficiency of 95%. The PEG-lipid micelles exhibited a sustained release behavior in the simulated lung fluid. Intratracheally administered polymeric micellar paclitaxel showed highest accumulation of paclitaxel in the lungs with AUC(0-12) in lungs being 45-fold higher than intravenously administered formulation and 3-fold higher than intratracheally delivered taxol. Paclitaxel concentration in other non-targeted tissues and plasma were significantly lower as compared to other groups. Furthermore, toxicity studies showed no significant increase in levels of lung injury markers in PEG(5000)-DSPE treated group as compared to saline-treated group. PEG(5000)-DSPE micelles delivered intratracheally were able to sustain highest paclitaxel concentrations in lungs for long periods of time, thus apprehending their suitability as pulmonary drug carriers.

Synthesis and biological evaluation of PMMA/MMT nanocomposite as denture base material

Inorganic-polymer nanocomposites are of significant interest for emerging materials due to their improved properties and unique combination of properties. Poly (methylmethacrylate) (PMMA)/montmorillonite (MMT) nanocomposites were prepared by in situ suspension polymerization with dodecylamine used as MMT-modifier. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the structures of the nanocomposites. Cytotoxicity test, hemolysis test, acute systemic toxicity test, oral mucous membrane irritation test, guinea-pig maximization test and mouse bone-marrow micronucleus test were used to evaluate the biocompatibility of PMMA/MMT nanocomposites. The results indicated that an exfoliated nanocomposite was achieved, and the resulting nanocomposites exhibited excellent biocompatibility as denture base material and had potential application in dental materials.

The mechanism of enhancement on oral absorption of paclitaxel by N-octyl-O-sulfate chitosan micelles

The overall objective of the present investigation was to demonstrate the effect of N-octyl-O-sulfate chitosan (NOSC) micelles on enhancing the oral absorption of paclitaxel (PTX) in vivo and in vitro, and identify the mechanism of this action of NOSC. In vivo, the oral bioavailability of PTX loaded in NOSC micelles (PTX-M) was 6-fold improved in comparison with that of an orally dosed Taxol(®). In the Caco-2 uptake studies, NOSC micelles brought about a significantly higher amount of PTX accumulated in Caco-2 cells via both clathrin- and caveolae-mediated endocytosis, and NOSC had the effect on inhibiting PTX secreted by P-glycoprotein (P-gp), which was also proved by the studies on rhodamine 123 incorporated in NOSC micelles, fluorescence labeled micelles. The mechanism of NOSC on P-gp inhibition was demonstrated in connection with interfering the P-gp ATPase by NOSC rather than reducing the P-gp expression. Moreover, NOSC with the concentration approaching the critical micellar concentration (CMC) had the strongest effect on P-gp inhibition. In the Caco-2 transport studies, the presence of verapamil and NOSC both improved the transport of Taxol(®), which further certified the effect of NOSC on P-gp inhibition, and PTX-M enhanced the permeability of PTX compared with Taxol(®). The apparent permeability coefficient (Papp) of PTX-M decreased significantly at 4 °C in comparison with at 37 °C, which indicated a predominant active endocytic mechanism for the transport of PTX-M, a P-gp-independent way. Furthermore, the transcytosis of PTX-M was via clathrin-mediated rather than caveolae-mediated. In addition, the transepithelial electrical resistance (TEER) of Caco-2 cell monolayers had no significant change during the transport study, which pointed out that NOSC had no effect on opening the intercellular tight junctions. Based on the obtained results, it is suggested that NOSC micelles might be a potentially applicable tool for enhancing the oral absorption of P-gp substrates.

Paclitaxel gelatin nanoparticles for intravesical bladder cancer therapy

PURPOSE

We have noted that inadequate drug delivery to tumor cells is a major cause of failed intravesical therapy for nonmuscle invading bladder cancer, partly due to the dilution of drug concentration by urine production during treatment. To address this problem we developed gelatin nanoparticles of paclitaxel designed to yield constant drug concentrations. The hypothesis that a constant, therapeutic concentration in urine, bladder tissue and tumors can be attained was evaluated in dogs.

MATERIALS AND METHODS

We studied drug release from paclitaxel gelatin nanoparticles in culture medium in vitro. In vivo studies were performed in tumor-free dogs and in pet dogs with naturally occurring transitional cell carcinoma, in which the pharmacokinetics of paclitaxel gelatin nanoparticles were determined in plasma, urine and tumors.

RESULTS

Paclitaxel release from paclitaxel gelatin nanoparticles in vitro and in vivo was rate limited by the drug solubility in aqueous medium. This property yielded constant drug concentrations independent of changes in urine volume during the 2-hour treatment. Intravesical paclitaxel gelatin nanoparticles showed low systemic absorption, and favorable bladder tissue/tumor targeting and retention properties with pharmacologically active concentrations retained in tumors for at least 1 week.

CONCLUSIONS

Constant drug release from paclitaxel gelatin nanoparticles may overcome the problem of drug dilution by newly produced urine and the sustained drug levels in tumors may decrease treatment frequency.

Enhanced oral absorption of paclitaxel in N-deoxycholic acid-N, O-hydroxyethyl chitosan micellar system

The overall goal of this study was to develop a micellar system of paclitaxel (PTX) to enhance its oral absorption. An amphiphilic chitosan derivative, N-deoxycholic acid-N, O-hydroxyethyl chitosan (DHC), was synthesized and characterized by FTIR, (1)H NMR, elemental analysis, and X-ray diffraction (XRD) techniques. The degree of substitution (DS) of hydroxyethyl group and deoxycholic acid group ranged from 89.5-114.5% and 1.11-8.17%, respectively. The critical micelle concentration (CMC) values of DHC decreased from 0.26 to 0.16 mg/mL as the DS of deoxycholic acid group increased. PTX was successfully loaded in DHC micelles with a high drug loading (31.68 ± 0.14%) and entrapment efficiency (77.57 ± 0.51%). The particle size of PTX-loaded DHC micelles ranged from 203.35 ± 2.19 to 236.70 ± 3.40 nm as the DS of deoxycholic acid group increased. After orally administration of PTX-loaded DHC micelles, the bioavailability was threefold compared with that of an orally dosed Taxol®. The single-pass intestinal perfusion studies (SPIP) showed that the intestinal absorption of micelles was via endocytosis involving a saturable process and a p-glycoprotein (P-gp)-independent way. All these indicated that the DHC micelles might be a promising tool for oral delivery of poorly water-soluble drugs.

Self-assembled micelles based on hydrophobically modified quaternized cellulose for drug delivery

Novel amphiphilic cationic cellulose (HMQC) derivatives carrying long chain alkyl groups as hydrophobic moieties and quaternary ammonium groups as hydrophilic moieties were synthesized. Structure and properties of the amphiphilic cellulose derivatives were characterized by elemental analysis, FT-IR, (1)H NMR, ζ-potential measurement, dynamic light scattering (DLS), fluorescence spectroscopy and transmission electron microscopy (TEM). The results revealed that HMQCs can be self-assembled into cationic micelles in distilled water with the average hydrodynamic radius of 320-430 nm. The cytotoxicity study showed that the HMQC exhibited low cytotoxicity. Prednisone acetate, a water insoluble anti-inflammation drug, was chosen as a model drug to investigate the utilization of self-assembled HMQC micelles as a delivery carrier for poorly water-soluble drugs. The study indicated that the prednisone acetate could be incorporated effectively in the self-assembled HMQC micelles and be controlled released.

Combined chemo-immunotherapy as a prospective strategy to combat cancer: a nanoparticle based approach

The prime objective of this study was to develop a combined chemo-immunotherapeutic formulation which could directly kill cancer cells as well as activate the immunosuppressed tumor microenvironment to mount a robust antitumor immune response. Paclitaxel (PTX) and SP-LPS (nontoxic derivative of lipopolysaccharide) were selected as anticancer drug and immunostimulant respectively. Poly(lactic-co-glycolic acid) (PLGA) based PTX and SP-LPS containing nanoparticles (TLNP) were prepared by the double-emulsion method (w/o/w) and characterized in terms of size, zeta potential and transmission electron microscopy (TEM). The release behavior of PTX and SP-LPS from the TLNP exhibited a biphasic pattern characterized by an initial burst followed by slow continuous release. In vitro anticancer activity of TLNP was found to be higher compared to PTX when studied in a tumor cell-splenocyte coculture system. TLNP activated murine monocytes induced the secretion of various proinflammatory cytokines. After iv administration of TLNP in tumor bearing C57BL/6 mice, the amount of PTX in the tumor mass was found to be higher in TLNP treated mice as compared to commercial Taxol group at all time points studied. In vitro studies suggest that nanoparticles containing PTX and SP-LPS have both direct cytotoxicity and immunostimulatory activity. Hence this might have potential as a chemo-immunotherapeutic formulation against cancer with advantage over present day chemotherapy with Taxol, in terms of tumor targeting, less toxicity and immunostimulation.

A ceramic-based anticancer drug delivery system to treat breast cancer

Drug delivery systems offer the advantage of sustained targeted release with minimal side effect. In the present study, the therapeutic efficacy of a porous silica-calcium phosphate nanocomposite (SCPC) as a new delivery system for 5-Fluorouracil (5-FU) was evaluated in vitro and in vivo. In vitro studies showed that two formulations; SCPC50/5-FU and SCPC75/5-FU hybrids were very cytotoxic for 4T1 mammary tumor cells. In contrast, control SCPCs without drug did not show any measurable toxic effect. Release kinetics studies showed that SCPC75/5-FU hybrid provided a burst release of 5-FU in the first 24 h followed by a sustained release of a therapeutic dose (30.7 microg/day) of the drug for up to 32 days. Moreover, subcutaneous implantation of SCPC75/5-FU hybrid disk in an immunocompetent murine model of breast cancer stopped 4T1 tumor growth. Blood analyses showed comparable concentrations of Ca, P and Si in animals implanted with or without SCPC75 disks. These results strongly suggest that SCPC/5-FU hybrids can provide an effective treatment for solid tumors with minimal side effects.

pH-Sensitive mPEG-Hz-Cholesterol Conjugates as a Liposome Delivery System

Hydrazone (Hz)-based pH-sensitive methoxy(polyethylene glycol)-cholesterol conjugates (mPEG-Hz-Chol), were synthesized and used to fabricate liposomes. The structures of the mPEG2000-Hz-Chol conjugate were confirmed by FT-IR and 1H-NMR; they were stable at pH 7.4 but sensitive to mild acid conditions (pH 5.5). Plain liposomes were also prepared with S100PC/ Chol, and the pH-insensitive liposomes with S100PC/Chol/mPEG2000-Chol for comparison; all the liposomes were similar in diameter ∼200 nm. In vitro, the pH-sensitive liposomes released more of the model drug, paclitaxel (PTX), than the plain liposomes. The pH-sensitive liposomes were less toxic than the plain liposomes and exhibited higher cellular uptake of PTX compared with pH-insensitive liposomes by human breast cancer cells (MCF-7). The pHsensitive mPEG2000-Hz-Chol liposomes are now being investigated as a potential new liposome drug delivery system.

Modified chitosan derivative micelle system for natural anti-tumor product gambogic acid delivery

A chitosan derivative micelle system was developed as the delivery system for a novel anti-tumor drug, gambogic acid (GA). The physicochemical and pharmaceutical properties of GA-loaded micelles (GA-M) were evaluated compared with the formulation GA-L-arginine (GA-L) injection, which entered phase I clinical trials. The results showed that GA-M had high GA-loading rate (29.8 +/- 0.17%), high entrapment efficiency (63.8 +/- 0.52%), and small particle size (108.2 +/- 0.8 nm). After i.v. administration at the dose of 4 mg/kg, the area under concentration-time curve (AUC) and elimination half-life (T(1/2)beta) of GA-M were all increased by 1.7-fold compared with GA-L in rat. Biodistribution study indicated that approximately 67% of GA in the GA-M group was distributed in the liver, while the value of the GA-L group was approximately 55%. Additionally, GA amount in the kidney was greatly reduced in the GA-M group. Also, GA-M was shown to reduce the acute toxicity after i.v. administration in mice compared with GA-L. The present study indicated that GA was rapidly eliminated from the blood and transferred to the tissues, especially the liver. Moreover, GA acute toxicity and irritation to vein were decreased.

Prostaglandin E1 encapsulated into lipid nanoparticles improves its anti-inflammatory effect with low side-effect

Prostaglandin E(1) (PGE1) shows various pharmacological activities including anti-inflammation. However, the rapid metabolization and inactivation of the intravenously administered PGE1 during the first passage through the lungs result in significant non-compliance in clinical trials which greatly limits its application. The aim of this work was to prepare the lipid nanoparticles loading PGE1 to improve its anti-inflammatory effect with low side-effect. The experimental results showed that PGE1 loaded lipid nanoparticles (PLNs) could be successfully prepared by high pressure homogenization with particle size 68.1+/-4.7 nm, zeta potential -3.32+/-0.37 mV and entrapment efficiency 92.1+/-1.3%. PLNs exhibited a sustained release with low burst drug release. PLNs could improve the inhibition effects of PGE1 on lipopolysaccharides (LPS)-induced TNF-alpha expression on macrophage RAW264.7 cells, and improve the inhibition of lymphocyte to endothelial cell adhesion and ICAM-1 adhesion molecule expression on HUVEC and MDA-MB-468 cell membrane. No allergenicity, vascular and muscle irritation were induced in animals by PLNs even at double of the highest drug concentration of clinical infusion. As a result, PLNs could be a more potential delivery system for PGE1 in the treatment of inflammation-related diseases.

Biodegradation, biodistribution and toxicity of chitosan

Chitosan is a natural polysaccharide that has attracted significant scientific interest during the last two decades. It is a potentially biologically compatible material that is chemically versatile (-NH2 groups and various M(w)). These two basic properties have been used by drug delivery and tissue engineering scientists to create a plethora of formulations and scaffolds that show promise in healthcare. Despite the high number of published studies, chitosan is not approved by the FDA for any product in drug delivery, and as a consequence very few biotech companies are using this material. This review will aim to provide information on these biological properties that affect chitosan's safe use in drug delivery. The term "Chitosan" represents a large group of structurally different chemical entities that may show different biodistribution, biodegradation and toxicological profiles. Here we aim to review research in this area and critically discuss chitosan's potential to be used as a generally regarded as safe (GRAS) material.

Simultaneous quantitative monitoring of drug-induced caspase cascade pathways in carcinoma cells

Caspases are the key mediators of apoptosis. The caspase cascade includes a series of events leading to the activation of initiator and downstream caspases in a cell. Analysis of the caspase cascade in intact cells, however, has generally been limited as the simultaneous monitoring of upstream and downstream caspases is not well executed. In an effort to monitor the activation of caspase cascades in an intact cell, high-content cellular imaging that allows simultaneous quantitative monitoring of caspase activation has been developed. This has great significance for the exploration of various cellular caspases involved in apoptotic pathways as possible therapeutic targets in the process of drug discovery. To explore the potential of simultaneous monitoring of caspase-mediated apoptotic pathways, human myeloid leukemia HL-60 cells were treated with SH-03 {(7S,7aR,13aS)-9,10-dimethoxy-3,3-dimethyl-7,7a,13,13a-tetrahydro-3H-chromeno [3,4-b]pyrano[2,3-h]chromen-7-ol} (a newly synthesized candidate), camptothecin or naringenin (agents known to induce apoptosis) with or without caspase inhibitors. SH-03 or naringenin treatment initiated the caspase cascade through an intrinsic apoptotic pathway, whereas camptothecin treatment triggered both intrinsic and extrinsic caspase cascades. We now report a new approach based on uniform threshold intensity distribution that facilitates rapid, quantitative monitoring of drug-induced caspase cascades through multi-spectral and multicolor imaging cytometry.

Non-cytotoxic, in situ gelable hydrogels composed of N-carboxyethyl chitosan and oxidized dextran

A series of in situ gelable hydrogels were prepared from oxidized dextran (Odex) and N-carboxyethyl chitosan (CEC) without any extraneous crosslinking agent. The gelation readily took place at physiological pH and body temperature. The gelation process was monitored rheologically, and the effect of the oxidation degree of dextran on the gelation process was investigated. The higher the oxidation degree of Odex, the faster the gelation. A highly porous hydrogel structure was revealed under scanning electron microscopy (SEM). Swelling and degradation of the Odex/CEC hydrogels in PBS showed that both swelling and degradation were related to the crosslinking density of the hydrogels. In particular, the hydrogels underwent fast mass loss in the first 2 weeks, followed by a more moderate degradation. The results of long-term cell viability tests revealed that the hydrogels were non-cytotoxic. Mouse fibroblasts were encapsulated in the hydrogels and cell viability was at least 95% within 3 days following encapsulation. Furthermore, cells entrapped inside the hydrogel assumed round shape initially but they gradually adapted to the new environment and spread-out to assume more spiny shapes. Additionally, the results from applying the Odex/CEC system to mice full-thickness transcutaneous wound models suggested that it was capable of enhancing wound healing.

Biodistribution and pharmacokinetic analysis of Paclitaxel and ceramide administered in multifunctional polymer-blend nanoparticles in drug resistant breast cancer model

In this study, we have investigated the biodistribution and pharmacokinetic analysis of paclitaxel (PTX) and the apoptotic signaling molecule, C6-ceramide (CER), when administered in a multifunctional polymer-blend nanoparticle formulation to female nude mice bearing an orthotopic drug sensitive MCF7 and multidrug resistant MCF7 TR (MDR-1 positive) human breast adenocarcinoma. A polymer-blend nanoparticle system was engineered to incorporate temporally controlled sequential release of the combination drug payload. Hereby, PTX was encapsulated in the pH-responsive rapid releasing polymer, poly(beta-amino ester) (PbAE), while CER was present in the slow releasing polymer, poly(D,L-lactide-co-glycolide) (PLGA) within these blend nanoparticles. When particle formulations were administered intravenously to MCF7 and MCF7 TR tumor bearing mice, higher concentrations of PTX were found in the blood due to longer retention time and an enhanced tumor accumulation relative to administration of free drug. In addition, the PLGA/PbAE blend nanoparticles were effective in enhancing the residence time of both drugs at the tumor site by reducing systemic clearance. Overall, these results are highly encouraging for development of multifunctional polymer-blend nanoparticle formulations that can be used for temporal-controlled administration of two drugs from a single formulation.

In vitro and in vivo studies on plasma-to-blood ratio of paclitaxel in human, rabbit and rat blood fractions

Many pharmacokinetic studies of paclitaxel formulations with or without Cremophor (CrEL) have been performed on experimental animals. However, limited studies describe the different pharmacokinetic behaviors of paclitaxel in animals. The different distribution of drug in blood fractions may have great effect on its pharmacokinetic behaviors. Our present study was designed to study the characteristics of paclitaxel distribution in human, rabbit and rat blood, by measuring plasma-to-blood ratio (PBR) of paclitaxel in vitro and in vivo, and analyzing the results of equilibrium dialysis of paclitaxel with erythrocyte, plasma and hemoglobin. It was demonstrated that the paclitaxel PBR values in rat, unlike those in rabbit, are most significantly different from those in human, which may be due to distinct affinity of paclitaxel to blood fractions among different species. The effect of CrEL on increasing paclitaxel plasma concentration and in vitro & in vivo correlation in animal PBR values were observed. The findings in this study are of significance in the evaluation of the newly developed formulations of paclitaxel.